[PAULUS libro singulari ad senatus consultum Turpillianum. ] §23.2.68.prIure gentium incestum committit, qui ex gradu ascendentium uel descendentium uxorem duxerit.
[PAULUS, in the Single Book on the Senatus Consultum Turpillianum.] He who marries a woman from the line of ascendants or descendants commits incest under the law of nations.
qui uero ex latere eam duxerit quam uetatur, uel adfinem quam impeditur, si quidem palam fecerit, leuius, si uero clam hoc commiserit, grauius punitur.
But he who marries a woman from the collateral line whom he is forbidden to marry, or an affine whom he is barred from marrying, is punished more lightly if indeed he did so openly, but more severely if he committed this secretly.
cuius diuersitatis illa ratio est: circa matrimonium quod ex latere non bene contrahitur palam delinquentes ut errantes maiore poena excusantur, clam committentes ut contumaces plectuntur.
The reason for this difference is as follows: regarding a marriage which is not properly contracted in the collateral line, those who offend openly are excused from the greater punishment as if acting in error, while those who commit it secretly are punished as contumaceous.